M-rk ward packard



(N6 Model.)

J.- PACKARD.

RHEOSVTAT.

Patented June 26 WITNESSES: w

WINVENTOR:

ATTORNEY.

Application tilt-d May ISLIFSE.

Eb i175 whom it may 072 00??? Be it known that L-JAiins WARD PAoitAnn, a citizen of the United States. residing at New orL in the county of New York and Stateot' .2" York, have invented certain new and use til improvements in ltlieostats; and. I do here- 'i declare the following to he a full, clear, and xect description of the invention, such will nab-lo others skilled in the art to which it apto make and use the same.

The object of my invention is to produce a rheostat heavy currents which can be cheaply made, easily repaired, and will not heat.

in the drawings, Figure 1 represents my heostat in side elevation. Fig. 2 is a plan of he some. Fig. 3 is a detail view showing the insulation between the cross bar and the divided portions of the sides of the frame.

The frame of my rheostat consists of the two cortical standards A and A, which are screwed to the bed-piece X. Upon thescstandards are adjnstably placetl'thc cross-pieces B B, which are held in place by the set-screws ca. These cross-pieces B B are made iii-two divided portions, 15 K, clearly shown in l ig. 2. Pass ing through or resting upon these divided. portions of the cross-pieces are the cross-bars D E E, 820. These cross-bars are insulated from the cross-pieces by he hardruhber rings, as shown in the detail View, Fig. 3. Upon the crossbnrs D E ll, &c., are strung the resistance-coils il 0 C C, &c. resistance coils, being arranged in the manner shown are connected-up in series.

The cable Iii furnishes a permanent electric connection between one terminal of the external electric circuit and the crossbar D, which latter is one terminal of the internal circuitoi' the resisniricecoils. The cable N furnishes the other terminal of the external electriccir- Connected with the cable I? are ,two branches, in a. which terminate in socket pieces I. P. (Most clearly shown in Fig. 2.) These socltctpicces fit over the ends of any of the crosshu-rs, E E, &e., and can be shifted from one-crossbar to another by hand.

in operation my rheostat is placed in circuit by connecting the terminals oi" the said circuit 3 t eeahles Iii and To vary the resistance it is only necessary toreinove one of the socket- Consequently these CATEQN forming part of Letters Patent No. 38109.1, dated June 26, 3.888.

Serial No. 274,436. (No model.)

i), having the permanent connection and the nearest socket-piece, since the current will he short-circuited through the branch, n or n, which presents the least resistance.

The advantages ofiny construction are ohvious. There is no wood or other inflammable materiel to be charred by the heating effects of heavy currents. the passage or" air through every part. and thus the'hcntiug effects are largely eounteracted. Every portion of the rluros. at is evnoscd to the eye of thcoperator and can he go n at readily for repairs, if any are necessary. There is always a perfect contact between one of th socketpieces and the crossimr upon which it rests, so that there is no sparl'iugganci wearing of the contact-surfaces when-the rlic is in use, as is frequently the case in other forms of apparatus or" this nature.

1 Having therefore described ,my invention both in essence and detail, what I claim as new a and desire to protect by Letters Patent. is-- .l. A. rheostat which has two independentlyadjustable contact-pieces to al'iord connection between; one terminal of the external circuit and the internal circuit of the resistance-coils, suhstautiztlly as described.

2. A rheostat which has two indcpeiitientiyadjustable coutacbpieccs to afford connection between one terminal of the ex al circuit and the internal circuit the il3SlSiilll(Q-C0ilS, said contact-pieces being in shunt relation one to the other substantially as described.

3. A rhcostat which has the i'ollowingparts in combination: a skeleton frame, a set of resistancocoils connected in series and insulated from the frame, an clcctricai conne on netwoen one of the series and one tcrmii'inl of the external. circiiit,iiiitl two independently ilii ill-iifllil l. contactpiec s which afford connec- Qiho rheostat is open for equal to the sum of the coils between the bar v tion b'ctween the other terminal of the extcroftwo'ol" its opposite sides, bntinsnlat-ed therenal circuit and the resistance-coils, tially as described.

4. A rheostat which has the following parts in combination: a skeleton frame, a set ot'resistance-coils connected in series and insulated from-the frame, an electrical connection between one end of the series and one term-final oft-he external circuit, and-two-independently adjustable contact-pieces which afford connection between the other terminalfof the extersnbslannal circuit and the resistance-coils, said con-.

tact-pieces being in shunt relation one to another.

5. A rheostat which has the following parts 1 l i l l from, a set of resistance-coils strung on saidbars and connected in series, an electrical conneetion between one terminal of the exterior .circnit and one end of the series of coils, and

two soeket- 'iieoes which are electrically eonneetcd to the other terminal of the exterior circuit, and which fit over the proiectingends of any of the said cross-bars, substantially as described] In testimony whereof I affix my s ignatnrein presence of two witnesses.

I film [Es WARD PACKARD. \Vitncsscs:

JNo. M.- ROBERTSON, (fins. II. GoRNE. 

